Bumping an old thread, but I'm curious about the theory behind the spark plug orientation. If they all face the same way, this should allow a more identical burn between cylinders, right? But what's the reason for having them face the exhaust valves?
Honda was nice enough to post a video of the R18 engine found in 2006+ Civics. You get a nice view of the spark plugs from about 0:43-0:45. The plug gaps are all facing the intake valves. Maybe this is just a marketing video, and I shouldn't read too much into the plug orientation?
New 1.8l i-VTEC Engine